PHP and Multithreading: A Lighthearted Look at Concurrency

4 min readMay 4, 2023
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Have you ever found yourself daydreaming about PHP and multithreading? Well, maybe not. But if you’re curious about how PHP handles concurrency, you’re in for a treat!

Multithreading is when you have parts in the same program or task doing things in parallel. PHP and multithreading go together like, well, oil and water. While PHP does have a PTHREAD extension (though it’s currently not maintained and it’s advised to use the parallel extension instead), it only supports multithreading at the command line level. But don’t worry my friend; we won’t dive into the depths of PTHREAD today.

You see, people often crave multithreading because they want to squeeze every ounce of power from their machine’s cores. But, PHP already does a fantastic job of keeping your cores busy by handling concurrent requests through web servers like PHP-FPM and there is no issue of not making use of all the cores in a machine like a standalone daemon or a CLI. So, you might say, PHP is already a multitasking powerhouse!

When it comes to PHP running on your frontend web server, you should treat long-running tasks like a hot potato. Toss them to a different set of servers using a message queue or job worker setup. That way, you can asynchronously manage jobs without clogging up your front-end server. Keep those frontend servers free for, well, serving the front end!

Think of it like a well-orchestrated ballet — your frontend server should dance gracefully with incoming requests and swiftly send responses back. But those long-running tasks? They belong in the background, like stagehands pulling the ropes.

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Just as you wouldn’t run your database on your frontend web service (I’m looking at you, daredevils), you should have a dedicated database server. This way, you can optimize hardware for specific tasks, such as providing a database server with ample memory.

Consider this tale of an e-commerce platform: a seemingly unified web application, but in reality, a modular masterpiece. Each aspect — product listings, cart management, and order checking — was hosted on separate server clusters. This modular approach allowed for optimal performance and scalability.

Now, I know what you’re thinking. “If PHP had multithreading, we could run everything on the frontend server, right?” Hold your horses, partner! That kind of setup just wouldn’t scale. PHP’s stateless, sandboxed design makes it a horizontally scalable champion. Threading would only encourage running background tasks on front-end servers, leading to chaos and anarchy in the world of web applications.

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In recent years, PHP has seen significant advancements with tools like React PHP and Swoole, which allow for asynchronous, non-blocking I/O operations in PHP. While these solutions provide new ways to handle concurrency in PHP, they are not a replacement for proper architecture when building web applications

With the arrival of PHP 8, we’ve got some new kids on the block: PHP Parallel and Fibers. PHP Parallel provides a new way to achieve concurrency using parallelism, while Fibers introduce cooperative multitasking, allowing you to write asynchronous code in a more straightforward, synchronous-looking way. Although these features are exciting and open up new possibilities, they should not encourage poor architectural choices or promote running heavy background tasks on front-end web servers.

While these tools can offer improved performance and concurrency, it’s essential not to lose sight of PHP’s core strengths and the importance of proper architecture in web applications. Remember to keep things modular and scalable, and your web application will sing like a well-orchestrated symphony.

In summary, multithreading in PHP isn’t the holy grail of performance. Instead, focus on building modular web applications that take advantage of PHP’s concurrency capabilities. With the right architecture, PHP can be the superhero of scalability that it was always meant to be.

So, the next time you find yourself pondering PHP and multithreading, remember this lighthearted tale and embrace the beauty of PHP’s concurrency capabilities. Happy coding!




Software Developer — I admire breaking up complex problems into understandable and sizeable bits, solving daily challenges with technology